Return of Reckoning

IIRC more skill points increases the base damage which is formulated with the 'dmg stat' co-efficient. It's more damage, but is it worth more abilities? Your choice.

Since respecing is free you could go respec all your points, check the tooltip damage of one of the mastery-related abilities, put one put. see how much the tooltip damage increased, then put one more point etc.

Did something simular on BW, 1 mastery point into aoe tree gives roughly 4tooltip damage on aoe abilities, and like 12damage to boiling blood.

With the Ironbreaker builds being as they are, likely not enough leftover to matter. Depends a lot on what you are planning on doing while 2handing if I am reading your original point correctly.